Method and apparatus for transferring orderly sequences of bottles made of thermoplastic material

ABSTRACT

An apparatus for processing plastic hollow bodies has a blow-moulding station, a device for introducing thereinto a sequence of trains of preforms, an ejection station adapted to separate the ejected hollow bodies, and devices provided downstream of the ejection station to handle the hollow bodies, the devices including a conveyor belt capable of being driven by a pulley and provided with plugs adapted to pick up the hollow bodies. The pulley is provided on its outer surface with a plurality of ejectors that are arranged to sequentially engage and disengage the pick-up plugs so as to release the blow-moulded hollow bodies therefrom. Beneath said ejectors there is arranged a guide which is adapted to intercept the so released hollow bodies, and which is provided with two parallel rails adapted to retain the hollow bodies by their neck portion and push them, preferably with jets of blown air, towards their utilization apparatuses.

DESCRIPTION

The present invention refers to an improved apparatus for handling on alarge-scale basis, and in an orderly sequential manner, containers madeof thermoplastic material, in particular polyethylene terephtalate (PET)and polypropylene (PP), by submitting appropriate semi-finished mouldedparts generally known as “parisons” or “preforms” to a so-calledblow-moulding process.

In particular, the present invention can be used in a most advantageousmanner when the described apparatus is associated to a preformproduction plant, i.e., a plant that is also known as a single-stageone, but can, of course, be effectively used also in connection withplants that are fed with previously produced preforms to only carry outthe final blow-moulding phase (two-stage plants).

As a matter of fact, these processes for the production of the abovecited kinds of containers are generally known to be able to beschematically divided into two basic topologies, single-stage andtwo-stage processes.

In two-stage processes, a previously moulded preform or parison in asubstantially amorphous state is heated up again to its preferredmolecular orientation temperature, at which it is then blow-moulded tothe desired shape. As used in this particular context, the term“two-stage process”, or simply “two-stage”, is intended to mean anyprocess that produces a preform or parison which must subsequently beheated up again from room temperature to the respective blow-mouldingtemperature.

On the contrary, single-stage processes are so defined owing to the factthat they are capable of moulding the so-called preform or parison, andtransferring the same preform or parison from the injection or extrusionmould (after it has cooled down to some appropriate temperature) to aconditioning station where the preform or parison is allowed to evenlybalance down to a preferred molecular orientation temperature. Thepreform or parison is then transferred to a blow-moulding mould, whereit is moulded to the desired shape.

The state of the art concerning the techniques implemented for solvingthe various problems in connection with the processes ofinjection-moulding or extrusion and blow-moulding of the preforms, aswell as the synchronization of all these processes with each other inview of increasing the productivity of the whole production plant, isexhaustively described in the European patent application EP 0 768 165,filed by the same Applicant, which also describes the most significantpatent literature existing on the matter and to which reference shouldtherefore be made.

Both above cited types of production methods involve the use of a (persè known) blow-moulding station and the therewith associated handlingmeans for transferring and releasing the preforms and/or theblow-moulded containers after the blow-moulding phase.

Largely known in the art are also the problems connected to the start-upof a single-stage plant. In particular, when such plants are beingstarted, the need arises technically for the plant to be brought tosteady-state conditions, which means the need for the blow-mouldingmoulds, and in particular the injection moulds in the stage where thepreforms are extruded/injection-moulded, to be brought to apre-determined temperature, before preforms with the desired propertiescan be obtained.

As a result, after the plant has been started, a certain quantity ofpreforms are unavoidably produced for a certain period of time, ornumber of cycles, which, owing to the preforms not yet having thedesired properties, cannot be used and must therefore be discarded.

To this purpose, such a type of plant is therefore started initially sothat only the section thereof devoted to the production of preforms isactually operated, wherein the preforms, after having been removed fromthe moulds, are handled and transferred in the usual manner, and areeventually moved across the blow-moulding station. Since such preformsare not yet capable to be used for blow forming, owing to the abovecited reasons, the blow-moulding station is not yet operating and, as aconsequence, the preforms move, without being actually processed,between the two blow-forming mould halves which remain in their openposition.

When they move out of the mould halves, the preforms, which are usuallyorganized in groups that move in a synchronized manner, otherwise knownas “preform trains” in the art, are transported, with generally per sèknown means, towards an ejection station where they are separated fromthe plant and usually discharged into appropriate bins or containers.Anyway, they are eliminated from the production process.

After a certain period of initial operation, the plant then reachessteady-state conditions, so that it can from then on be operated in allof its sections.

As a consequence, the blow-moulding station is then running, so that thepreforms are blow formed there and converted into finished containerswhich are again transported, in the same manner as illustrated above, tothe ejection station that discharges them into appropriate baskets, binsor similar containers adapted to collect the finished product, fromwhich they are then brought to the utilization plants, which are usuallythe filling plants.

Therefore, it clearly emerges that the need for two groups of productsto be separated, i.e., the preforms or the blow-formed containers thatare produced during the two subsequent phases of operation understart-up and steady-state conditions of the plant, practically involvesthe need for a phase to be provided of selective separation from theplant and, therefore, also of selective separation of the containersthat are blow-moulded after the steady-state conditions of the planthave been reached.

It clearly ensues that such a need for a selective separation phase tobe included and operating even after the plant has reached steady-stateconditions, causes the orderly and substantially continuous flow ofcontainers from the blow-moulding station to the utilization plantsthereof to be practically interrupted. As a result, such a separationphase generates a considerable diseconomy since it practically preventsthe production flow of blow-moulded containers from being automaticallysynchronized with the utilization flow of the same containers in theplants, such as filling plants, provided downstream.

As far as two-stage plants are concerned, i.e., practically the preformtemperature conditioning station and the blow-moulding station, thesituation is substantially similar to the one that has been justdescribed with reference to single-stage plants, owing to a persistingneed for a start-up phase to be provided in order to bring all of thevarious sections of the plant up to steady-state temperature.

Also in connection with two-stage plants, therefore, the need stillarises for an initial run of preforms to be produced, which must then be“discarded” and separated selectively from the plant, so that the samedrawbacks and diseconomies as the aforementioned ones are encounteredalso in these kind of plants.

Therefore, the need arises of providing an apparatus able tosequencially carry a plurality of containers and to release them in atransfer means apt to engage them and to move them from a specificworking station to a different one. From EP 0 596 487 a transfer meansof containers is known that is mainly using a moving chain operated in aclosed loop. However, such a means appears to be rather complicated andburdensome both in the construction and during operation. Furthermore,it is missing of automatic means of expulsion, collecting andtransfering of the containers as they reach a specific working station.

SUMMARY OF THE INVENTION

In consideration of what has been stated above, it is therefore a manpurpose of the present invention to provide an apparatus and a methodapplying to the phases that follow the actual blow-moulding phase of aplant for the production of blow-moulded containers, so as to eliminateall of the above cited drawbacks and enable such the plant to feed in asubstantially continuous and automatic manner the utilization plantsarranged downstream, without any interposition of phases that arenon-automatic or such as to anyway cause the continuity of flow ofblow-moulded containers feeding such utilization plants to beinterrupted. Furthermore, such an apparatus must be easily implementedthrough the use of readily available techniques and, therefore, be areasonably low-cost one.

Such a main aim of the present invention, along with further featuresthereof, is reached in an apparatus that is made and operates as recitedin the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may take the form of a preferred embodiment suchas the one that is described in detail below by way of non-limitingexample with reference to the accompany drawings, in which:

FIG. 1 is a vertical side view of an apparatus according to the presentinvention;

FIG. 2 is a view along a section of FIG. 1;

FIGS. 3 and 4 are views along sections of FIG. 1;

FIG. 5 is a view along another section of FIG. 1; and

FIG. 6 is an enlarged view of a detail of FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

The basic novelity of the present invention lies in the use ofparticular methods and means for releasing and separating theblow-moulded containers from a conveyor belt to which they are appliedby means of appropriate devices that are generally known in the art as“pick-up plugs”.

The release means, along with the thereto associated means for routingthe blow-moulded, finished containers towards the utilization linesthereof, are arranged downstream of the traditional ejection stationswhich in turn are provided downstream of the blow-moulding stations.

Referring now to FIG. 1, which is a schematical view of a traditionalblow-moulding plant with associated finished-container ejection station,the same plant can be noticed to include a blow-moulding station 1(which is shown here only symbolically), a conveyor belt 3 adapted tofeed the blow-moulding station 1 with synchronized groups or trains ofpreforms and provided with a plurality of pick-up plugs 4 adapted toengage the necks 5 of respective preforms to transport them along thedirection of movement of the conveyor belt 3, and a wheel 6 acting as adriving pulley for the conveyor belt 3.

Downstream of the blow-moulding station 1 there is arranged a partejection station 1, of a per sè known type and therefore only shown hereas generally indicated at 8, which is provided with means adapted toseparate in a synchronized manner the various successive trains ofpreforms or blow-moulded containers from the related pick-up plugsprovided on the conveyor belt 3.

Once such a separation has so taken place, the preforms or blow-mouldedcontainers fall by gravity into appropriate bins or similar containers(not shown) that are then sent to appropriate utilization lines (orrecovery/recycling lines in the case of rejects).

As has already been pointed out earlier in this description, non-blownpreforms are produced during the plant start-up period beforesteady-state conditions are reached and, after the steady-stateconditions are eventually reached, blow-moulded containers are producedthat are ready for further use, i.e., usually for filling.

The present invention provides the kind of plant with means which, whenarranged downstream of the ejection station 8, are capable of separatingsolely the blow-moulded containers from the conveyor belt 3, as well astransferring the same containers, in an orderly sequence and at acontinuous, constant rate, onto a special transport line adapted toroute the containers towards their final utilization, i.e., fillingapparatuses.

It clearly emerges that, if the means are arranged downstream of theejection station 8, the latter must be provided with selectivelyactuatable devices adapted not to eject, but rather to retain theblow-moulded containers in order to enable such containers to travel onuntil they reach the zone where they are orderly separated therefrom andsent in a continuous manner to the transport line for conveyance towardsthe utilization apparatuses.

The actuation means shall of course be such as to also enable non-blownpreforms to be ejected during the plant start-up period beforesteady-state conditions are reached.

With reference to the Figures, the means arranged downstream of theejection station 8 can be noticed to include:

a wheel 6 acting as a driving pulley and provided with ejection elements10 adapted to successively engage and disengage inside the pick-up plugs4 so as to eject the blow-moulded hollow bodies that are appliedthereto; and

a guide comprising two rails 11 and 12 arranged at a distance D that isslightly smaller than a diameter C of a neck 13 of the hollow bodies,but larger that a diameter B of a blown portion 14 of the hollow bodysituated immediately beneath the respective neck portion, as illustratedin FIG. 6; from the illustration in FIG. 4, it can be noticed that theguide is arranged in a substantially horizontal position and is alignedwith the vertical projection of the conveyor belt 3 and the pulley 6.

At the side of the rails, and parallel with respect thereto, there areprovided respective hollow conduits 16, 17 which are provided with aplurality of slits 18 and 19, respectively, facing the interior of theguide at the same height as the one at which the necks of the hollowbodies come to situate themselves; the slits are aligned according toand oriented in the direction of movement of the blow-moulded hollowbodies.

The hollow conduits are connected, via appropriate conduits 20, toair-flow generators (blowers) adapted to generate such air flows at anappropriate rate and pressure.

The operations of the above cited means is as follows:

As best shown in FIGS. 1, 2 and 3, the pick-up plugs 4 are caused tomove forwards by the conveyor belt 3 until they reach a position inwhich the respective necks 13 engage with their upper portion the rails11 and 12 (FIG. 4) without actually touching them. As they move furtheron along their travel path, respective ejection elements 10 provided onthe outer side of the pulley 6 penetrate the interior of the pick-upplugs 4 and push off the respective hollow bodies therefrom, as this isbest shown in FIG. 3.

Since they are no longer supported by the respective pick-up plugs 4,the blow-moulded bodies tend to fall, but are immediately retained bytheir respective neck portion by the rails 11 and 12.

The physical arrangement of the various above described elements is suchthat the position in which the pick-up plugs 4 enter the rails comesbefore the position in which the ejection elements 10 engage the necksof the respective hollow bodies, so that all of the hollow bodies areseparate in a sequence from the respective pick-up plugs 4 and sent,again in a sequence, along the guide.

After the hollow bodies are so ejected by the respective ejection meansand then so retained by the rails, the movement thereof along the railsmay be ensured by any of a plurality of means, provided that these areadapted to automatically and sequentially transport the hollow bodiestowards their utilization plants, wherein the means may be driven in anyof various known methods, e.g., electrically, mechanically,pneumatically or the like.

In a preferred manner, according to an improved embodiment of thepresent invention the means are based on an air jet that, owing to itsbeing suitably oriented and coming from the plurality of subsequentslits 18 and 19 provided along the travel path of the hollow bodies,takes the form of an air jet blowing in a substantially continuousmanner onto the various necks 5 of the hollow bodies and so pushes themin an orderly manner along the rails up to the utilization plants.

Although the invention has been described here based on the example ofpreferred embodiments thereof and using a generally known terminology,it shall not be intended as being limited thereby, since it is wellwithin the ability of anyone skilled in the art to develop a number ofvariants from the teachings thereof. The appended claims shall thereforebe understood as covering all such possible obvious modifications thatare within the ability of those skilled in the art and do not departfrom the actual scope of the present invention.

What is claimed is:
 1. An apparatus for processing hollow bodies ofplastic material, which may be both blow-moulded containers and not yetblow-moulded preforms, and transferring said hollow bodies intocollecting means or towards utilization lines, comprising at least ablow-moulding station, means arranged downstream of said blow-mouldingstation, and including: an ejection station adapted to separate saidhollow bodies removed from or coming out of said blow-moulding stationand corresponding to trains of the preforms that are fed in a sequenceto said blow-moulding station, and means that are arranged downstream ofsaid ejection station for handling said hollow bodies, these meanscomprising a conveyor belt adapted to be driven by a pulley and providedwith members or pick-up plugs for picking up and releasing said hollowbodies, a pulley arranged vertically and adapted to drive said conveyorbelt, separation and transfer means downstream of said ejection stationadapted to separate said hollow bodies from the respective pick-up plugsin the form of blow-moulded containers and send them in a substantiallycontinuous sequence towards their utilization apparatuses, characterizedin that: said separation means comprise said pulley which is provided onits outer surface with a plurality of ejecting elements arranged at apre-established distance and adapted to orderly and sequentially engageinteriors of said pick-up plugs so as to separate said blow-mouldedhollow bodies therefrom, and beneath said ejecting elements there isarranged a guide that is adapted to intercept and retain said soseparated blow-moulded hollow bodies, said guide comprising two parallelrails.
 2. An apparatus according to claim 1, characterized in that saidhandling means comprise two hollow conduits, which are aligned alongsaid two respective rails and in which there is provided a respectiveplurality of slits facing an interior of the respective rail andoriented in a direction of movement of the blow-moulded hollow bodies.3. An apparatus according to claim 2, characterized in that said hollowconduits are connected to one or more blowing means generating an airflow that is conveyed into said conduits.
 4. An apparatus according toclaim 3, characterized in that air-flow pressure, distance, width andorientation of the slits, as well as a configuration of the rails areadapted to enable said blow-moulded hollow bodies to be pushed in anorderly sequence towards their utilization apparatuses.
 5. An apparatusaccording to claim 1, characterized in that it is provided with meansfor actuating and controlling an operation of said blow-moulding stationand said ejection station in such a manner as to selectively bring aboutfollowing operational modes: blow-moulding station non-operating,ejection station operating; and blow-moulding station operating,ejection station non-operating, under actuation of said air-flowgenerating means.
 6. A method for producing and transferring hollowblow-moulded plastic bodies, comprising the phases of: blow mouldingsaid plastic bodies, sequentially and orderly separating said plasticbodies from a conveyor belt at a predetermined rate, said conveyor beltbeing activated by at least a pulley provided with pick-up plugs forpicking up and releasing said hollow bodies, placing said hollow bodiesin an orderly row along a transfer means able to support and guide themby means of a pair of rails that are adapted to retain said hollowbodies by their respective neck portion, transferring said plasticbodies to their respective apparatuses, characterized in that: theseparation of said plastic bodies from said conveyor belt is carried outby pushing with a plurality of ejecting elements, arranged on an outersurface of said pulley, an interior of said plugs as to separate saidhollow bodies therefrom, after being separated from said conveyor, saidhollow bodies are caused to move along by a plurality of air jets blownat an appropriate angle that is preferably symmetrical with respect totheir movement direction.
 7. A method according to claim 6,characterized in that said hollow bodies, so arranged in said pair ofsupporting rails, are caused to move along by the plurality of air jetsblown at the appropriate angle that is preferably symmetrical withrespect to the direction of movement of said hollow bodies.
 8. Anapparatus according to claim 2, characterized in that it is providedwith means for actuating and controlling an operation of saidblow-moulding station and said ejection station in such a manner as toselectively bring about following operational modes: blow-mouldingstation non-operating, ejection station operating; and blow-mouldingstation operating, ejection station non-operating, under actuation ofsaid air-flow generating means.
 9. An apparatus according to claim 3,characterized in that it is provided with means for actuating andcontrolling an operation of said blow-moulding station and said ejectionstation in such a manner as to selectively bring about followingoperational modes: blow-moulding station non-operating, ejection stationoperating; and blow-moulding station operating, ejection stationnon-operating, under actuation of said air-flow generating means.
 10. Anapparatus according to claim 4, characterized in that it is providedwith means for actuating and controlling an operation of saidblow-moulding station and said ejection station in such a manner as toselectively bring about following operational modes: blow-mouldingstation non-operating, ejection station operating; and blow-mouldingstation operating, ejection station non-operating, under actuation ofsaid air-flow generating means.